Sound-producing instrument



July 24, .1928.

'w. BRANDEGGER;

SOUND PRODUCING INSTRUMENT Filed Aug. 18, 1926 Patented July 24. 1928.

UNITED STATES 1,678,553 PATENT OFFICE.

WILLY BRANDEGGER, OF STUTTGART, GERMANY.

SOUND-PRODUCING INSTRUMENT.

Application filed August 18, 1926, Serial No. 129,991, and in Germanyjugust 27, 1825.

My invention refers to sound producing instruments and more especially to a horn of the type in which a plate or disc-shaped body is mounted in. the way of the air current in such manner as to face the air outlet and to act as a. valve capable of throttling the air passag Such throttling plates or discs were hitherto mounted in the horn in such manner that they were either fixed near their circumference or in the centre or were loosely supported between shoulders acting on these circumferential partsand merely limiting the width of oscillation without, however, fixing the plate or disc in place.

If the plate or disc is fixed at its circumference or in the centre, not only the oscillating capacity is impaired but also the force of sound is greatly reduced. On the other hand such plates or discs which are freely supported at their circumference so as to be bodily movable within certain limits tend to clatter.

In the instrument according to the present invention the disc or plate-shaped oscillatory body is arranged in such manner as to be capable of producing vigorous and pure sound oscillations without being allowed to oscillate bodily in such manner that the undesirable oscillatory phenomena can occur. To this end the oscillatory plate or disc is supported at or near its circumference in a resilient manner by elastic arms extending radially inwardly and having their inner ends fixed to the instrument in a suitable manner. By this means the disc or plate is attached to the instrument in an elastic manner and in consequence of the circumstance that the points of fixation are disposed in close proximity to the centre, all variations of form and all strains occasioned by variations in temperature or moisture are rendered innocuous. The plates or discs arranged as above described can further be made stronger than was hitherto possible.

In the drawings aflixed to'tnis specification and forming part thereof several modifications of an instrument embodying my invention aige illustrated diagrammatically by way of example.

In the drawings Fig. l is an axial section of the sound producing portion of the horn and Figs. 2, 3, 4 and 5 are plan views of four diflerent forms of an oscillatory plate or disc adapted for use in this horn.

Fig. 6 is a cross section on the line A-B in Fig. 5,

Fig. 7 or plate,

Figs. 8 and 9 are an axial section and a side elevation, respectively, partly in section, illustrating means for varying the position of the plate relative to the air duct.

Figs. 10 and 11 are axial sections drawn to a smaller scale which show different modes of action of the disc or plate.

In all the modifications shown in Figs. 16 a is the acoustically operative portion of the oscillatory body which has the form of a disc or plate cut out in such manner as to present elastic arms for fixing the plate in position. It is, however, also possible to support the disc or plate by means of separate arms attached to it by any suitable means such as welding, soldering, riveting or the like.

The central portion a of the disc or plate is arranged in the way of the air current indicated by the arrows in Figs. 1 and'8. As shown more particularly in Figs. 6-11, this portion will act either towards closing or towards throttling outlet 1) of the air duct. I can, however, also mount'on the disc or plate a separate valve body 0 (Fig. 1).

The part a is preferably mounted in the centre of an annular structure 6 which may, however, also adopt a polygonal form (Fig. 3), arms (1 connecting the parts a and e as shown more particularly in Figs. 2, 3 and 5. The elastic supporting arms proper f are shown in Figs. 2 and 3 as extending inwardly from the annular support 6, holes indicated near their inner ends serving for mounting the oscillatory body in place in the horn.

In the modification shown in Fig. 4 a full disc or plate is'shown in which inwardly directed elastic arms 7 are formed by stamp mg.

In the form shown in Fig. 5 the arms 7 are formed as radial outwardly directed extensions of the annular part 6, these extensions (one of which is shown in dot-anddash lines in Fig. 5) being then bent around so that their free ends are directed towards the centre (Fig. 6). In an oscillatory body of'this latter kind the elastic sus-. pension of the central part a isparticularly eflicient. If desired the arms f in this modification may even extend below the central portion a.

is a cross section of a double-disc varying the jecting noses Instead of fixing the arms 7 in a rigid manner by means of screws or rivets, they may also be secured in place between proor the like in a movable manner,

In order to effect a damping and the prevention of undesirable impure oscillations, I

,can mount on top of or around the disc or In the form shown in Fig. 1 the disc or plate, instead of being mounted directly in the horn, is shown as being secured to a separate movable support 9 which may act as a whole after the manner of a valve. This form is particularly suitable in cases where the valve is intended to move in the direction of the air current, so as to open an The air current produced for instance by means of a rubber ball or the like causes the support 9 to be forced down on its seat and therefore rests applied against this seat,

.while the sound is formed, substantially in the same manner as if it were fixed on the seat. If, however, the rubber ballv is released, the support 9 will be lifted free of its seat after the manner of a valve and will al-- low the air flowing back through the horn into the rubber ball to flow around the support and the sound producing disc or body a, e without this body and its support being set oscillating thereby.

Figs. 8 and 9 illustrate the means for position of. the oscillatory disc of plate relative to the air outlet. In the form shown in Fig. 8 the part i which may for instance carry the rubber ball, is merely screwed down upon the part is carrying the horn, while in the arrangement shown in Fig. 9 a threaded nipple m is mounted in the part L- which can be displaced therein from without by means of a head screw n tending arms being mounted in a ring p surrounding the part 1: and extending into the nipple m across a slot 0 in the part 1:. By thus varying the distance between the oscillatory body a or the valve body 0 mounted thereon (Fig. 1) relative to the air inlet or outlet the force of sound can be varied without dismantling the instrument. This is useful also in case that foreign bodies should have entered the instrument which must be removed therefrom in order to render it operative again.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

I claim 1. Sound producing instrument comprising an air tube, a plate-shaped body facing an end of said tube, a ring surrounding said body, resilient arms connecting said body with said ring and resilient arms extending inwardly from said-ring, the inner ends of said inwardly extending arms being fixed to hold said body in position. air outlet of increased cross-sectional area.

2. Sound producing instrument comprising an air tube, a plate-shaped body facing an end of said tube, a valve mounted on said body, a ring surrounding said body and connected therewith and resilient arms extending inwardly from said ring, the inner ends of said arms being fixed to hold said body in position.

3. Sound producing instrument comprising an air tube, a plate-shaped body facing an end of said tube, a ring surrounding said body, resilient arms connecting said body with said ring and resilient arms extending inwardly from said ring, but in a different plane, the inner ends of said inwardly extixed to hold said body in position.

4. Sound producing instrument comprising an air tube, a plate-shaped body facing an end of said tube, an auxiliary plate applied against said body and resilient arms holding said body in position. 1

In testimony whereof I aflix my signature.

WILLY BRANDEGGER. 

